Skin is the largest organ of the human body. It has important functions in protecting the body from infection, toxins, microbes, and radiation. Disorders of skin not only compromise these functions, but also cause significantly psychological, social, and occupational problems. A significant portion of the world's population is afflicted with skin problems. Indeed, tens of millions of Americans are affected by of skin disorders such as rosacea, acne, pityriasis rosea, urticaria, and erythema. These disorders account for a large portion of annual healthcare costs, in addition to non-financial costs, such as intractable itching, sleep deprivation, time spent in treatment, inconvenience, and associated social stigma. There is a need for treatment of skin disorders.